1) The phenomenon known as "black holes" occurs when matter is crushed into an infinitely small space, creating a gravitational pull so strong that nothing can escape.

2) The musical "Les Misérables" is one of the longest-running shows in the West End and Broadway, with over 13,000 performances.

3) The longest English word is "pneumonoultramicroscopicsilicovolcanoconiosis," which refers to a lung disease caused by inhaling very fine silica dust.

4) The word "country" contains three vowels: O, U, and Y.